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Proceedings Paper

Calibration procedures and application of the PTB photomask CD standard
Author(s): W. Häßler-Grohne; C.G. Frase; S. Czerkas; K. Dirscherl; B. Bodermann; W. Mirandé; G. Ehret; H. Bosse
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Paper Abstract

The PTB has developed a new 6025 photomask standard for calibration of CD metrology tools in a joint project with partners from mask industry in Germany [1]. We report on the design of the standard, its calibration procedures and the results of recent round robin measurements on this standard in which different CD metrology tools of the project partners were involved. The layout of the CD photomask standard (COG and 193 nm halftone PSM) contains isolated as well as dense features in both tones with nominal CD down to 100 nm. Calibration of the standards was performed at PTB by UV microscopy and LV-SEM, supported by additional AFM measurements for edge slope characterization. For analysis of UV microscopy as well as SEM images appropriate signal modeling was applied, which allowed to extract the feature widths at the top of the structures as well as the widths at 50% height of the structures. In this contribution we will also discuss results of a recent round robin comparison measurement performed on up-to-date metrology tools available for CD metrology today by means of one of the newly developed CD standards. We used PTB calibrated CD standards in order to provide a set of CD references for the different tools which then should be used in a "blind" comparison to calibrate an unknown CD mask of the same design as the standards. Different type of CD metrology instrumentation, namely standard UV and DUV optical as well as DUV water immersion CD microscopes, a new UV dark field optical microscope, CD-SEM, and AFM/SFM were applied. The outcome of this comparison on cur-rently applied metrology instrumentation provides a valuable source of information for cross calibration issues which are discussed in mask industry today.

Paper Details

Date Published: 9 November 2005
PDF: 12 pages
Proc. SPIE 5992, 25th Annual BACUS Symposium on Photomask Technology, 59924O (9 November 2005); doi: 10.1117/12.632779
Show Author Affiliations
W. Häßler-Grohne, Physikalisch-Technische Bundesanstalt (Germany)
C.G. Frase, Physikalisch-Technische Bundesanstalt (Germany)
S. Czerkas, Physikalisch-Technische Bundesanstalt (Germany)
K. Dirscherl, Physikalisch-Technische Bundesanstalt (Germany)
B. Bodermann, Physikalisch-Technische Bundesanstalt (Germany)
W. Mirandé, Physikalisch-Technische Bundesanstalt (Germany)
G. Ehret, Physikalisch-Technische Bundesanstalt (Germany)
H. Bosse, Physikalisch-Technische Bundesanstalt (Germany)

Published in SPIE Proceedings Vol. 5992:
25th Annual BACUS Symposium on Photomask Technology
J. Tracy Weed; Patrick M. Martin, Editor(s)

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